Group buy link
Here you have it.
http://www.diyaudio.com/forums/grou...regulator-group-buy-interest.html#post3639545
regards,
Carlos
Here you have it.
http://www.diyaudio.com/forums/grou...regulator-group-buy-interest.html#post3639545
regards,
Carlos
About power dissipation into the series pass transistor
into the Dx Power supply.
Here you have a study of the worst case scenario..... i cannot suggest you heatsink brand, model and code number because i do not use the traditional method to select heatsinks...i use aluminum blade and my calculation is made to discover how many watts that specific heatsink will dissipate in audio watts, not heat watts..something different that apply directly to my own needs to use junk heatsinks.... as i did that since i was very young...when i was a kid and had no money to buy a heatsink...so...a method was developed to figure out if the that specific cooking pot will be good to be transformer in a heatsink.
But you have watts...heat watts..then you select your heatsinks..one to each rail...they must hold three power output transistors...must have a room for that.
Worst case means that real life your heatsinks gonna be warm..not hot...they may be 10 degrees above the environement temperature.
regards,
Carlos
into the Dx Power supply.
Here you have a study of the worst case scenario..... i cannot suggest you heatsink brand, model and code number because i do not use the traditional method to select heatsinks...i use aluminum blade and my calculation is made to discover how many watts that specific heatsink will dissipate in audio watts, not heat watts..something different that apply directly to my own needs to use junk heatsinks.... as i did that since i was very young...when i was a kid and had no money to buy a heatsink...so...a method was developed to figure out if the that specific cooking pot will be good to be transformer in a heatsink.
But you have watts...heat watts..then you select your heatsinks..one to each rail...they must hold three power output transistors...must have a room for that.
Worst case means that real life your heatsinks gonna be warm..not hot...they may be 10 degrees above the environement temperature.
regards,
Carlos
Attachments
In my case mister Terry I use MJL3281A and MJL1302A and I didn't have no problems, MJL21193/21194 are good ones too, Carlos suggested MJL4281A/4302A but you decide what is best for you.
the BD139 do you mean this one marked in red in this image? I have seen friends installed by wire well insulated to the main power heat sink it can be done why not? hey guess what? I just got my new solder yeah!
Regards
Juan
the BD139 do you mean this one marked in red in this image? I have seen friends installed by wire well insulated to the main power heat sink it can be done why not? hey guess what? I just got my new solder yeah!
Regards
Juan
Attachments
I know that Carlos suggests MJL4281/4302, and I have several, but would rather save those for Amplifiers and use the MJL22193/94 here if there will be no difference. I have lots of these and they seem to be not as good for amps unless designed for them. I thought maybe they would work just as well here as they serve a different purpose. Still learning. Sorry about the BD139 question, I forgot what thread I was in. Since I already asked, I was talking about Q39.
Thanks, Terry
Thanks, Terry
NO!... do not use these transistors Terry
I have checked..these transistors oscillate....they are the only ones i said to Brazilians not to use.
Do not use them together Dx Super A.
Man....gladly you told me...you would kill your tweeters and also kill your power amplifier...cannot use them without make huge modifications.
I do not instruct the modifications as these transistors are a hell in earth..these ones and MJ340/350
regards,
Carlos
I have checked..these transistors oscillate....they are the only ones i said to Brazilians not to use.
Do not use them together Dx Super A.
Man....gladly you told me...you would kill your tweeters and also kill your power amplifier...cannot use them without make huge modifications.
I do not instruct the modifications as these transistors are a hell in earth..these ones and MJ340/350
regards,
Carlos
I think you should be fine I'm going to use TIP35C/36C that according to the On data can handle 25 amps but in reality the amplifier will not drain that is just the max according to the PDF information.
this transistors you have should be good
MJL21193(PNP) MJL21194(NPN) should be fine 16 amperes
Regards
Juasn
this transistors you have should be good
MJL21193(PNP) MJL21194(NPN) should be fine 16 amperes
Regards
Juasn
In the supply there's no problem at all
If you use it into the amplifier you will have to increase the compensation capacitor...this transistor is the only one gave me hard time.
Also MJ340/350 is a problem...i would prefere to met the devil than to see these transistors.
But for the supply it will not hurt us.
regards,
Carlos
If you use it into the amplifier you will have to increase the compensation capacitor...this transistor is the only one gave me hard time.
Also MJ340/350 is a problem...i would prefere to met the devil than to see these transistors.
But for the supply it will not hurt us.
regards,
Carlos
We now have a builder's thread to the Dx Supply and Dx Super A
It is called Dx Super A builder's thread.
Post there your progress...pictures please, and use the thread to your needs, to post questions and to report any problem you find while building.
If etched at home...much better..we are there to help you.
regards,
Carlos
It is called Dx Super A builder's thread.
Post there your progress...pictures please, and use the thread to your needs, to post questions and to report any problem you find while building.
If etched at home...much better..we are there to help you.
regards,
Carlos
Supply was tested with TIP35 and TIP36
Of couse if you install better transistors the result will be better..and if you install worse transistors the final result will be worse related the power it will be able to deliver.
Observe we have dissipation, voltage and current to think about.
Modifications must be made under your own risk, i can give you warranty the circuit will operate fine, together the Dx Super A, IF the circuit respect the original schematic and layout.
Having modifications, them complaints must be adressed to the one made the modifications if something result bad.
I imagine (just imagination) these transistors may work fine..but i do not have them to test, also i do not want to test them.... they created me so many troubles when installed into the Dx Super A that i want to see the devil smoking than to see these transistors dear Terry.
I have to do this, or i would be testing several transistors...and they are too many..no way to do this..so, i test one...and for this one i give you warranty of nice operation....otherwise warranty is voided.
This amplifier was massivelly built in Brazil...and my people asked me to select a transistor they can find anywhere in redneck towns from the Amazon jungle to the extreme cold South of my Country...then was selected the TIP35/36 for that reason.
I cannot buy all transistors, all options and test them all...and these ones i do not want them even for free.
Regulators using series pass transistors have a terrible problem...if you short the output and fuse no good to open fast. then the series pass transistors becomes a short from colector to emitter...the output of the supply increases to the rectified and filtered voltage..... our amplifier cannot operate with more than 42 volts.... or into dinamic operation all BD139 and BD140 will short and will kill the output too....so...this stuff is series and error in that site may result you calling fire soldiers help and preparing a good land to bury your dead amplifier.
Check the supply before you connect it to the power amplifier.. adjust it to have 42 plus 42 volts in the output...put a resistive load (4.2 ohms) and drain 10 amperes for 3 minutes, to each rail, to be sure it will hold the job.
If your supply voltage, the rectified and filtered voltage, is higher than 50 volts..then let the stuff operating for 10 minutes to see if the heat is excessive or not..heatsinks cannot measure more than 55 degrées celsius because power transistor thermal derated dissipation depends on the temperature.
This means 840 watts of heat and consumption!...not an easy task to perform.
Use wire resistor you can have from the heating element of an electric shower (is this the name?)... cut it into 4.2 ohms piece and put it inside a basket having water (no salt in that water)
regards,
Carlos
Of couse if you install better transistors the result will be better..and if you install worse transistors the final result will be worse related the power it will be able to deliver.
Observe we have dissipation, voltage and current to think about.
Modifications must be made under your own risk, i can give you warranty the circuit will operate fine, together the Dx Super A, IF the circuit respect the original schematic and layout.
Having modifications, them complaints must be adressed to the one made the modifications if something result bad.
I imagine (just imagination) these transistors may work fine..but i do not have them to test, also i do not want to test them.... they created me so many troubles when installed into the Dx Super A that i want to see the devil smoking than to see these transistors dear Terry.
I have to do this, or i would be testing several transistors...and they are too many..no way to do this..so, i test one...and for this one i give you warranty of nice operation....otherwise warranty is voided.
This amplifier was massivelly built in Brazil...and my people asked me to select a transistor they can find anywhere in redneck towns from the Amazon jungle to the extreme cold South of my Country...then was selected the TIP35/36 for that reason.
I cannot buy all transistors, all options and test them all...and these ones i do not want them even for free.
Regulators using series pass transistors have a terrible problem...if you short the output and fuse no good to open fast. then the series pass transistors becomes a short from colector to emitter...the output of the supply increases to the rectified and filtered voltage..... our amplifier cannot operate with more than 42 volts.... or into dinamic operation all BD139 and BD140 will short and will kill the output too....so...this stuff is series and error in that site may result you calling fire soldiers help and preparing a good land to bury your dead amplifier.
Check the supply before you connect it to the power amplifier.. adjust it to have 42 plus 42 volts in the output...put a resistive load (4.2 ohms) and drain 10 amperes for 3 minutes, to each rail, to be sure it will hold the job.
If your supply voltage, the rectified and filtered voltage, is higher than 50 volts..then let the stuff operating for 10 minutes to see if the heat is excessive or not..heatsinks cannot measure more than 55 degrées celsius because power transistor thermal derated dissipation depends on the temperature.
This means 840 watts of heat and consumption!...not an easy task to perform.
Use wire resistor you can have from the heating element of an electric shower (is this the name?)... cut it into 4.2 ohms piece and put it inside a basket having water (no salt in that water)
regards,
Carlos
Attachments
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I am planning to use a 25-0-25vac transformer for my Super A. I only hooked up the 40-0-40vac transformer to the PS yesterday to test it. You guys say now that you designed for TIP35C but the spec I got was for MJL4281. That transistor is 15A Maximum DC Collector Current while the MJL21193 is 16A. The light bulb tester I used is 7.6 ohm but is only 150W. How many amps does the Super A need? I thought it was mainly A/B in operation.\
Thanks, Terry
Thanks, Terry
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